Some heating systems generate very small quantities of waste water from combustion condensate and/or from humidifiers. It is common practice to get rid of this waste water by means of a drain pipe through the foundation wall of the building which has such a system. In some installations this drain pipe becomes plugged with ice frozen from the waste water. Current practice is the use of electrical heat tape on waste water pipes to prevent this freezing.
There are situations where the waste water is in a low location and a gravity drain cannot be used to carry the waste water away from the heating system. In these locations a pump is sometimes used to get rid of the water. In these installations water is released in batches or cycles. To the inventors knowledge, in these installations intended function of the pump is solely to lift the water.